Patient-Reported Barriers to Colorectal Cancer Screening: The aim is to describe the factors that primary care patients identify as their reason(s) for not undergoing screening for colorectal cancer (CRC) and the relative importance they assign to each factor. Factors of interest include all potential reasons cited by patients, ranging from cognitive and attitudinal determinants of intention to operational impediments. All such reasons are described in this study as barriers. The setting is 12 primary care practices participating in a practice-based research network in Virginia. Using ACORN administrative data, we will identify a sample of 6100 patients, age 50-75. Beginning in month 7, these patients will receive a postal survey that will ask respondents to quantify the relative importance of a detailed list of potential barriers to CRC screening. The estimated 1600 responses will undergo statistical analysis to produce an epidemiologic distribution of the relative importance of barriers in the non-adherent primary care population. Differences in barrier profiles will be examined across patient subgroups, such as age, gender, race, education, income, geographic setting, stage of change, and clinical circumstances. Before it is fielded, the postal survey will undergo development (including analysis of a general open-ended question about perceived barriers to CRC screening to be added to an existing ACORN survey sent to 1000 patients) and validation in months 1-6 to ensure comprehensiveness in addressing all potentially important barriers. The steps in development will include a systematic review of the literature and the use of an analytic matrix to construct a complete list of barriers, analysis of responses to the open-ended survey question to identify unrecognized barriers and to capture the natural language patients use to describe them, review by experts in CRC screening behavior, and patient focus groups to obtain further feedback and to pilot test the instrument. Provider and patient focus groups will inform final interpretation of the barriers survey results. The study will provide essential data for prioritizing strategies to improve CRC screening rates.